Use different UV mapping with multiple textures
For the moment, the text and the background texture share the same UV, so what you're doing is just scaling the UV for both the text and the background texture.
If you want to put a text over a background texture without affecting the texture you need to use another method, like mixing the text and background into a Mix Shader with the alpha of the text as factor of the Mix Shader, then create a second UV map for the text and use a UV Map node before the text node with this second UV map selected.